Editorial Type:
Article Category: Research Article
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Online Publication Date: 11 Mar 2022

Populational Differentiation in Boana bischoffi (Anura, Hylidae): Revisiting the Issue Using Molecular, Morphological, and Acoustic Data

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Page Range: 110 – 119
DOI: 10.1670/20-121
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ABSTRACT

Boana bischoffi was originally described from the Brazilian state of Rio Grande do Sul and has Boana multilineata from São Paulo as a junior synonym. The history of its nomenclature reflects the varying interpretation of the dorsal color pattern of the two different populations. We reevaluate the problem of taxonomic recognition of Boana multilineata based on molecular, morphometric, and acoustic data. The molecular data revealed two major clades that are partially concordant with the morphological and acoustic differentiation. Morphometric analyses revealed elements of differentiation between populations in snout–vent length (SVL) and head shape, which were patterns not detected previously. Discrimination considering call features was substantial, even complete in a discriminant analysis. Despite these differences, we refrain from resurrecting the name B. multilineata due to the existence of putative introgression zones, the effect of SVL in call dominant frequency, and lack of taxonomically relevant differences. Boana bischoffi might represent a case of incipient speciation.

Copyright: Copyright 2022 Society for the Study of Amphibians and Reptiles 2022
Fig. 1.
Fig. 1.

Map of South and Southeast Brazil depicting the sampling localities of Boana bischoffi specimens used in the genetic analyses. The localities were classified in accordance with the two clades found or at sites where specimens of both were found in close range.

Fig. 2.
Fig. 2.

Maximum likelihood phylogenetic tree of Boana bischoffi based on 169 sequences of the mitochondrial ND2 gene. There are two clades, namely, one containing specimens from the northern population (N) and the other containing specimens from the southern population (S). Striped and nonstriped individuals are indicated by black and gray circles, respectively. The northern clade contains striped individuals only, whereas the southern clade contains both striped and nonstriped phenotypes, which are found sympatrically at the northernmost distribution of the southern population. Ultrafast bootstrap support values of >90% are indicated on tree branches.

Fig. 3.
Fig. 3.

Snout–vent length–head width relationship of northern and southern clades of Boana bischoffi (linear smooth added). Only the difference in intercept is significant (F = 21; P < 0.001).

Fig. 4.
Fig. 4.

Audiospectrograms and oscillograms of call type A of both clades of Boana bischoffi in the same time scale. Left: southern specimen (São Francisco de Paula, Pró-Mata, RS; air, 15°C); right: northern specimen (Atibaia, SP; air, 21°C). Note the differences in duration and dominant frequency. Insets: adult males from each clade.

Fig. 5.
Fig. 5.

Audiospectrograms and oscillograms of call type B of both clades of Boana bischoffi on the same time scale. Left: southern specimen (São Francisco de Paula, Pró-Mata, RS; air, 15°C); right: northern specimen (Atibaia, SP; air, 21°C).

Fig. 6.
Fig. 6.

Boxplot of four acoustic traits of both studied clades of Boana bischoffi. The differences in frequency are significant (P < 0.002). South had 20 and north had 13 recorded males.

Fig. 7.
Fig. 7.

Density function of the first DAPC discriminant axis considering acoustic traits of the northern and southern clades of Boana bischoffi. Note the complete discrimination between both. The internal box highlights the 11 axes comprising 95% of the explained variance. n = 20 males to south and 13 to north.

Contributor Notes

6 Corresponding Author. E-mail: aagiaretta@gmail.com
Accepted: 05 Aug 2021
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